Weaving machines in the form of generic-type shaft machines are well known. In such machines, the shaft frames or harnesses are activated individually or in a coordinated manner toward positions for open or closed sheds. When weaving is in progress, warp and weft threads represent a swinging system. During weaving, it is important for the thread tensions to be able to be checked and kept within certain prescribed ranges so that the finished woven product can be produced having the desired quality and characteristics. Various attempts have been made to achieve the necessary control of the various constructional and functional parts of the weaving machine and the various qualities and characteristics of the warp and weft threads. These attempts have been more or less successful.